Many athletic floors, such as basketball floors, volleyball courts, ballroom dance floors, bowling lanes and similar indoor facilities for athletic endeavors, can be provided with a relatively heavy sub-floor and a decorative thin floor covering which contains in printed fashion, all free throw lanes, centerlines, boundaries and other indicia particularly useful to the particular athletic game conducted upon the floor. Additionally, through photographic reproduction processes, a particularly beautiful wooden floor may be photographed and used as a floor covering. Ordinarily, these panels have been made in relatively large sheets, for example, 5.times.12 feet, which are then adhered to the sub-floor to make the finished floor appearance.
One of the problems that has been existent in the adhesive application of decorative floor sheets to a sub-floor has been the difficulty of obtaining a complete bond of the relatively thin laminate throughout its interface with the sub-floor and particularly to obtain a solid overall surface bonding when using adhesives which contain solvents which must be driven out of the adhesive layer in order to make the adhesive perform its intended function. It is extremely important in athletic floors, such as the basketball, volleyball and bowling lane floors, that the laminate has no unadhered areas which would cause the bouncing of the ball or the rolling of the ball to vary from one part of the floor to another.
Workmen employed to apply decorative floor sheets to a sub-floor are also subject to human error in the placement of any one sheet, which in the past could only be replaced by a physical chipping or scraping of the sheet loose from the sub-floor with attendant damage to the sub-floor, requiring repair before a replacement sheet could be applied. Damaged surface sheets can require replacement, particularly in bowling lanes where bowlers may loft the bowling ball beyond the foul line, causing damage to a portion of the lane partway down the lane from the foul line. The General Electric Company has produced a particularly decorative high pressure melamine resin laminate called "Perma-Lane".RTM., including an exposed surface appearance of a most beautiful bowling lane of wood. The sheets for use on the bowling lanes thus reproduce a particularly pleasing appearance of wood grain although the laminate is a photographic reproduction of an actual finished wood lane. The problem of removing a single sheet from such a lane and replacing the removed sheet with a new sheet has been troublesome in that it is difficult to chip out one sheet without damage to the adjacent sheets as well as the sub-floor below the damaged sheet. Removal of residual adhesive has also been difficult.
Prior practice followed to lay synthetic plastic laminate materials on bowling lanes has involved the application in the bowling establishment of a chlorinated contact-type adhesive to the uncoated sheets and the sub-floor. Either a roller or spray coating method was used to apply the contact adhesive to the underside of the decorative sheets and over the exposed sub-floor of the lane. These sheets were allowed to remain open for a time so that the solvent, which comprises about 80% of the coating material, could evaporate. Ordinarily, such hand coating resulted in ridges and valleys in the adhesive so that the eventual contact of the laminate onto the sub-floor did not result in 100% contact throughout the mating surfaces. Even under pressure rolling there resulted not enough flow of the adhesive to obtain 100% contact. In addition to this contact problem, the chlorine being heavier than air, presented a problem of exhaustion and removal, many workmen being adversely affected physically by the presence of the chlorine-based solvent. Many other contact adhesives utilize solvents which are either toxic or highly flammable, and thus are quite difficult to use in public places where a floor covering is to be installed.
There has existed a need for an improved method of laying and correcting the laying of decorative floor sheets upon sub-floors for athletic floors, which can eliminate the problems of toxic solvents and eliminate cleanup time for over spray, over rolled and/or accidentally wrongly applied adhesives, and yet provide a solid sounding laminate upon the sub-floor under all conditions of use.